These look like hours and minutes because the second number in each pair is less than 60.
There appear to be 28 hrs:min to add together.
Sum of first 6: 22:25;
Sum of 2nd 6: 22:04;
Sum of 3rd 6: 22:21;
Sum of 4th 6: 21:52;
Sum of 4: 13:40
TOTAL: 102:22 (average 3:39)